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  1. The pathogen that causes new coronary pneumonia is a new type of coronavirus, which is closely related to the previously familiar severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV). Infected patients will have fever, fatigue, and dry cough as the main clinical manifestations. In severe cases, acute respiratory distress syndrome will progress rapidly, or even die. So far, no specific drugs and vaccines have been approved for marketing. After the new type of coronavirus (SARS-CoV-2) invades host cells, it begins to replicate in large numbers. The two processes of transcription and replication of the genetic material RNA genome are the core. The transcription of genetic material will finally be translated into the structural constituent protein of the new virus, and its replication will form the RNA genome of the new virus. RNA-dependent RNA polymerases (RdRp), also known as non-structural protein 12 (nsp12), can be assembled with multiple other non-structural proteins to form an efficient RNA synthesis "machine". As the core component of this transcriptional replication machine, RNA polymerase is one of the most important antiviral drug targets. Disrupting its function is expected to prevent virus replication and ultimately achieve the goal of treatment. The research on the drug targets of the new coronavirus, especially RNA polymerase, is very important for the research and development of such targeted drugs and the verification of the pharmacodynamic mechanism. The structure of the complex analyzed shows that the RNA polymerase of the new coronavirus has the conservative characteristics of other viral RNA polymerases, and contains the NiRAN (Nidovirus RdRp-associated nucleotidyltransferase) characteristic domain of the Nidovirus; at the same time, viral RNA polymerization enzymes and virus non-structural proteins nsp7 and nsp8 constitute the core unit of transcription and replication machinery. Excitingly, the researchers also discovered for the first time a unique "β hairpin" domain at the N-terminus of the RNA polymerase of the new coronavirus. The discovery of this domain is to clarify the biology of the new coronavirus RNA polymerase. Through in-depth analysis of the atomic resolution structure, the research team discovered the key amino acid residues for the function of the new coronavirus RNA polymerase, and through the "hepatitis C virus polymerase ns5b-Sofosbuvir" effect. The structure of the “molecular” complex was compared, and the possible mode of action of the effector molecules (that is, the final product after metabolism) of remdesivir and fapilavir in inhibiting the new coronavirus RNA polymerase was proposed. This study is the first to finely describe the internal structure of the transcription and replication machinery of the new coronavirus "RdRp-nsp7-nsp8", and shows how the effector molecules of drug candidates such as Radixivir and fapilavir can precisely target and inhibit viral RNA synthesis. Furthermore, a reasonable mechanism explanation was put forward for exerting pharmacodynamic activity, which laid an important theoretical foundation for the in-depth study of the molecular mechanism of the new coronavirus replication, and opened up a new way for the development of specific drugs against new coronary pneumonia. In addition, the "Anti-Coronavirus Research Alliance" formed by the research team of Shanghai University of Science and Technology and its collaborators also jointly published the important research results of the new coronavirus on Nature "Structure of Mpro from COVID-19 virus and discovery of its inhibitors" "It is the first to successfully analyze the high-resolution three-dimensional structure of the main protease (Mpro), the key drug target of the new coronavirus, and to use three different drug discovery strategies to find inhibitors against the new coronavirus. In the research strategy designed from scratch, the "Alliance" found that the Michael receptor N3 is a potent inhibitor of the main protease, and was the first to analyze the 2.1Å high-resolution complex structure of the main protease-N3 (and later Increase to 1.7Å), which is also the world's first three-dimensional structure of the new coronavirus protein to be resolved. In order to facilitate relevant scientific and technological workers to develop antiviral drugs targeting this enzyme as soon as possible, the "Alliance" for the key research issue published the research results for the first time and published the structure in the Protein Data Bank (PDB). Since January 26, the team has directly provided data to the laboratories of more than 300 universities, research institutions and enterprises. This structure was selected as the February Molecule of the Month by PDB protein structure database, and was reported by PDB. Since then, the "Alliance" has continued to jointly use virtual screening and high-throughput screening strategies to screen more than 10,000 old drugs, clinical drugs, and natural active products, and found several species that have significant inhibitory effects on the main protease. Lead drugs, including disulfiram, carmofur, ebselen, shikonin, Tideglusib and PX-12. Subsequent anti-coronavirus experiments showed that both ebselen and N3 can significantly inhibit the replication of the neocoronavirus at the cellular level. It is worth mentioning that ebselen has been used in clinical trials for the treatment of various diseases such as hearing impairment (completed the second clinical phase), and has a good safety performance. The above-mentioned research results have laid an important foundation for the rapid development of anti-coronary pneumonia drugs with clinical potential.
  2. Abstract: Similar to SARS-CoV, SARS-CoV-2 is also a family member of coronavirus. But why is it leading to such a serious situation and when can we get rid of it? This article will explain the details about the development and future trends of SARS-CoV-2. As of July 1, 2020, the number of people diagnosed with COVID-19 worldwide has reached 11,669,259, and the death toll is as high as 539,906. On the frontal battlefield, there are still many doctors and nurses around the world struggling and working hard to save more lives. You may still remember the SARS epidemic caused by SARS-CoV in 2013. The virus started in Guangdong, China and a total of 5327 clinically diagnosed cases and 349 deaths have been reported in Mainland China. It also belongs to coronavirus, but why is this novel coronavirus caused by SARS-CoV-2 more serious than the similar virus of 2013? Coronavirus is a kind of pathogen that mainly causes respiratory and intestinal diseases, which mainly comes from domestic animals, poultry and wild animals (such as civet cats, bats). SARS-CoV can cause infection of the lower respiratory tract and induce pneumonia. The onset is rapid and highly contagious, with fever as the first symptom, with chills, headache, muscle aches, general fatigue and diarrhea gradually developed. Patients who are seriously ill may suffer from respiratory distress syndrome. The novel coronavirus, SARS-CoV-2, will infect the upper and lower respiratory tracts at the same time, which also allows it to spread like flu. A difference is that after the first symptoms of the patient, there are a large amount of viruses in the nose and throat of the upper respiratory tract, and the virus level in the nasal cavity is higher. At present, the most difficult challenge is those who are infected without symptoms. Although they do not show any symptoms, the virus levels in their bodies are comparable to those of symptomatic patients. Therefore, they not only have hidden characteristics, but also have the ability to be contagious, which makes it difficult to control the epidemic. In addition, SARS-CoV-2 has the characteristics of strong contagion, high population susceptibility, long incubation period, and diversified clinical manifestations, posing a huge threat to people's health and seriously affecting people's normal work and life. Experts of respiratory diseases said that the pneumonia caused by SARS-CoV-2 is likely to turn into a chronic, long-term human disease like the flu. As SARS-CoV is highly transmissible and pathogenic with the main attack organ the lungs, it is not easy to survive for a long time, and it cannot continue to spread. However, SARS-CoV-2 can also attack the kidneys, heart and other organs, thus is more difficult to cure. Scientists from Creative Biolabs, a CRO service provider once did a lot of research on SARS-CoV and MERS said, "We still know very little about SARS-CoV-2, but every study is a small piece of this huge virus puzzle." One thing is clear, protection against infections will most likely not stop the virus from spreading, but it will slow its spread. Many countries are currently conducting many antiviral drug tests for patients infected by SARS-CoV-2. And the vaccine may be available by next fall. Therefore, the more we slow down the spread, the better we can deal with this virus. In this long historical process, vaccination can be said to be the only more effective preventive measure. During the influenza epidemic season, comprehensive measures such as influenza vaccination are taken to prevent it, which has shown being very effective in controlling the influenza epidemic. In response to SARS-CoV-2, more and more vaccine candidates are currently undergoing evaluation and clinical trials worldwide and this number will increase substantially in the future. What distinguishes humans from other creatures is that humans have sufficient wisdom, courage, and perseverance. It’s believed that with global efforts, a safe and effective vaccine can be available as soon as possible.
  3. The early success rate of establishing the PDX model is extremely low, which is largely due to the rejection of the transplanted material by the host immune system. Although methods such as X-ray irradiation and thymectomy have been used to suppress the host's immune system, the development of the PDX model has largely benefited from the production of immunodeficient host mice. The first breakthrough was the development of nude mice. In 1962, Scottish doctor Issacso and others first discovered individual hairless mice in non-inbred albino mice, but did not conduct an in-depth analysis of them. In 1966, Flanagan from the Institute of Animal Genetics in Edinburgh confirmed that this hairless mouse was caused by allelic mutations on the chromosomes. He believed that it was a new spontaneous mutant and named it "Nude" mouse. Flanagan also found that female nude mice had extremely low fertility and could not raise their offspring due to poor breast development, but unfortunately he did not find the most important feature of nude mice, athymic glands. In 1968, Pantelouris from the University of Strathclyde in Scotland discovered athymic glands in nude mice obtained from the Institute of Animal Genetics in Edinburgh, which aroused great interest among medical biologists around the world. Nude mice are congenital hairless, athymic, and completely lacking in T lymphocyte function, and do not produce rejection response to xenotransplantation. Therefore, they are especially suitable for xenotransplantation of xenogeneic animal tissues and human tumor xenotransplantation, and are expected to replace thymectomy mice. In 1969, Danish scholar Rygaard successfully transplanted human colon cancer tumors into three nude mice for the first time. Six days after tumor transplantation, tumor tissue was found at the transplanted site. On the 40th day of tumor transplantation, the original 2×2×2mm tumor tissue had grown to 10×20×25mm in two of the nude mice, and 5×5×20mm in the other nude mouse. No signs of tumor growth were found in normal mice in the control group. As a result, scholars have established many PDX tumor models by transplanting various types of tumor tissues into nude mice. In 1983, Bosma, GC and others discovered a severe combined immunodeficiency CB17-SCID mouse, which lacks mature T cells and B cells, but the innate immune system retained in the body such as normal NK cells is not good for humans. Long-term colonization of source cells. In 1995, Jackson Lab used non-obese diabetic mice NOD/Lt to cross with SCID mice, and NOD-SCID mice were produced. This hybrid breed inhibits the activity of NK cells and is accompanied by defects in the innate immune system. Therefore, it is an animal model with more severe immunodeficiency, easier xenotransplantation success and stable application. However, NOD-SCID develops thymoma in an average of 8.5 months, so long-term models are not suitable. In 2002, the Japan Institute of Experimental Animals (CIEA) bred NOG mice. They successfully established a severely insufficiency immune system by crossing NOD/scid mice and γ-chain IL-2 receptor knockout (IL2rγKO) mice. Compared with NOD-scid mice, the survival rate of human cell and tissue transplantation in NOG mice is significantly improved. At the same time, it can implant a higher proportion of normal or cancerous human cells and tissues. In 2005, Jackson Lab in the United States developed NOD-scid gamma (NSG) mice. Due to genetic mutations, these mice have defects in T and B lymphocytes and the gamma chain gene of IL2 receptor, which has important immunoregulatory functions, was knocked out. In addition, NK cells also lose their function and can be used to transplant human cells and tissues without causing traditional immune responses. They are currently the most ideal recipient mice for humanized tissue transplantation. Subsequently, some scholars transplanted human hematopoietic stem cells (HSC) into these mice to form humanized hematopoietic and immune system reconstruction mice, which proved to be very effective human-derived mice. In addition, there are PBMC models in which human peripheral blood mononuclear cells are directly injected into severe immunodeficiency mice for immune reconstitution; human embryonic liver and thymus are co-transplanted under the kidney capsule of immunodeficiency mice, and at the same time BLT models are established by injecting hepatic hematopoietic stem cells from the same embryo into mice. These models are also widely used in the research and construction of PDX models and are effective tools for studying human diseases. In recent decades, with the widespread use of immunodeficient mice, a large number of PDX tumor models have been successfully established. These models retain the histopathology, molecular characteristics and drug response of their parent tumors, can reproduce tumor heterogeneity that cell line systems have not captured, and show potential clinical trial response prediction capabilities at the population level. In view of this, the PDX model provides a powerful tool and has been widely used to study cancer biology and assist in the preclinical setting of personalized cancer treatment and drug screening.
  4. Antibody-drug conjugate (ADC) is a humanized or human monoclonal antibody that is conjugated to a highly cytotoxic small molecule (payload) through a chemical linker. It is a novel form of treatment and is used in cancer chemotherapy. This new antibody-based molecular platform can selectively deliver effective cytotoxic payloads to target cancer cells compared with traditional chemotherapy, thereby improving efficacy, reducing systemic toxicity, and having better pharmacokinetics (PK)/Pharmacodynamics (PD) and bio-distribution. Driven by the success of Adcetris® and Kadcyla® approved by the FDA, this drug class is developing rapidly along with approximately 60 ADCs currently in clinical trials. In this article, we briefly reviewed the molecular aspects of each ADC component (antibody, payload, and linker), and then mainly discussed traditional and new technologies for successfully constructing clinically effective ADC coupling and linker chemistry. From the point of view of medicinal chemistry and pharmacology, current efforts in conjugation and connection chemistry will provide deeper insights into the molecular design and strategies of clinically effective ADCs. The development of site-specific conjugation methods for the construction of homogeneous ADCs, especially ways to improve ADC design will open the way for new cancer treatment methods. An introduction In the past half century, with the development of chemotherapy, the treatment of cancer has improved significantly. In addition to surgical resection, radiotherapy, targeted therapy using small molecules or monoclonal antibodies, and recent immunotherapy, chemotherapy using cytotoxic agents is the main treatment option. Chemotherapy is perfected by screening and developing small molecules that can selectively cause cancer cell death by inhibiting microtubule function, DNA synthesis or protein function. Although chemotherapy has achieved great success in the treatment of cancer, especially leukemia, there are still difficult problems, such as the development of drug resistance mechanisms. Serious adverse reactions caused by off-target cytotoxicity may worsen the patient’s quality of life, leading to drug withdrawal. This fact makes clinicians and medicinal chemists reluctant to pursue more potent cytotoxic drugs to treat cancer. In this case, the use of highly cytotoxic agents combined with cell targeting molecules has become a potential clinical strategy. In particular, antibody-drug conjugates (ADC), humanized or human monoclonal antibodies conjugated to cytotoxic small molecules via chemical linkers, may undergo fundamental changes in the design and administration of cancer chemotherapy. The platform can target cancer cells and selectively deliver highly cytotoxic drugs, thereby creating a broad therapeutic Indeed, successful clinical results using ADCs have inspired scientists in the biomedical research community to further advance this new platform to the next generation of cancer treatments. In this article, we reviewed the molecular aspects of ADCs, the latest developments in ADCs that have been successfully used in clinical applications, and the coupling and connection technologies used to successfully construct ADCs. A brief history In 1913, German physician and scientist Paul Ehrlich first proposed the concept of selectively delivering toxic drugs to target cells. Forty-five years later, his targeted therapy concept was proved for the first time in the form of ADC, where methotrexate was conjugated with a leukemia cell targeting antibody. In early research, polyclonal antibodies were the main targeting agent. In 1983, the first use of anti-carcinoembryonic antigen antibody-vinblastine conjugate for ADC human clinical trials, and reported promising results. Advances in antibody engineering technology, including the production of humanized antibodies, have promoted ADC research. The first-generation ADC consisting of chimeric or humanized antibodies was tested in the 1990s. Finally, further major efforts on practical therapies led to the FDA-approved ADC: Gimumab ozogamicin (Mylotarg®) for CD33-positive acute myeloid leukemia in 2000, and for CD30-positive relapsed or refractory Hodgkin’s lymphoma in 2011 brentuximab vedotin (Adcetris®). Anaplastic large cell lymphoma and trastuzumab Emtansine (Kadcyla®) were used in HER2-positive breast cancer in 2013. However, Mylotarg® was withdrawn from the market in 2010 due to lack of clinical benefit and lethal high toxicity compared to standard chemotherapy. Despite this setback, ADC technology is still developing rapidly, and about 60 ADCs are currently in clinical trials. In addition to immunotherapy using checkpoint inhibitors, this emerging chemotherapeutic molecular platform is expected to significantly increase its market share as one of its largest markets. The most effective anti-cancer therapy in the near future. The structure and mechanism of ADC Another important consideration is the limited number of payload molecules that can be effectively delivered to target cells. If it is assumed that the efficiency of each step in the ADC mechanism is 50% (biodistribution, binding to antigen, internalization, release of payload, intracellular stability of payload, and binding of payload to target), then only 1.56% administered drug molecules can enter the target cell. In fact, the estimated actual intake is much lower than this assumption (less than 0.01% per gram of tumor injection). Therefore, in order to maximize the therapeutic efficiency of using ADC, the cytotoxicity of the payload must be high enough to effectively eradicate target cells, and ideally should be in the picomolar range. It is very important to choose important toxic drugs as payloads, and ideal drugs have inherent selectivity to target cancer cells. Certain types of non-cancer cells may be able to internalize ADC through non-specific pinocytosis or crystallizable fragmentation (Fc) region receptor-mediated endocytosis. In addition, the payload can be released when it degrades into circulating blood. Therefore, the payload is mainly selected based on the above considerations; anti-mitotic agents are usually less toxic to non-cancer cells than to cancer cells, and are payloads that are mainly used in FDA-approved ADC and ADC clinical trials. In addition to calicheamicin (for Mylotarg®), auristatin (for Adcetris®) and maytansinoid (for Kadcyla®), a new type of highly effective anti-mitotic compound has been explored for ADC loading: Carmycin, pyrrolobenzodiazepine dimer (PBD) mannosides, mannosins, and tubulolysin analogs are such examples. To be continued in Part II…
  5. CD Genomics, an innovative sequencing and genotyping company, recently announced the launch of its new website with brand new product and service ranges and easy-access custom design. Gene Panel is an invaluable tool to analyze parallel gene expression for disease-associated mutations. Among them, next-generation sequencing (NGS) technologies are perhaps the most widely used approaches, which can analyze genetic mutations of large sample-size projects and facilitate research on human well-being. In the meantime, some non-NGS technologies may offer alternations for gene panel with a much more affordable price. CD Genomics Disease Panel is a one-stop destination for kinds of sequencing and reagents needs. Their catalog features hundreds of products such as Ready-to-Use NGS Panel for oncology, genetic disorder, genotyping, pathogen infections, Custom Panel Product and Non-NGS Panel, which can promote researchers’ disease research, biomarker discovery, molecular diagnostic application and targeted drug development. The newly launched website also features updated service descriptions and details, and a new Resource page. The services range from Predesigned NGS Panel for cancer, inherited disease, pathogens and pharmacogenomics testing, Tumor Mutational Burden Analysis, Custom NGS Panel, to Non-NGS Panel, for example, MassARRAY, Multiplex SNaPshot, Multiplex Ligation-Dependent Probe Amplification and ARMS-PCR for Sequence Variation Analysis. Moreover, customers searching for a new addition to the backyard can decide between the listed items and others. “CD Genomics can quickly respond to customers’ primers design or probes determination requirements. The accumulation of each measurement ensures a shorter turnaround time. Their comprehensive quality control and verification ensure the accuracy of results. I’d like to recommend the appropriate technology for gene-targeted detection to other researchers or institutions.” Said by a client, Jonson Smith. The company has an Illumina platform for variant detection. Multiple disease-related genes and regions of interest can be detected in a single assay. CD Genomics is a professional sequencing company with extensive experience in detecting genetic mutations such as SNPs, indels, copy number variations, and DNA methylation. About CD Genomics CD Genomics enjoys a high reputation for sequencing, microarray analysis, library construction and genotyping, providing reliable services to pharmaceutical and biotechnology companies as well as academia and government agencies. Based on rich experience in targeted sequencing, CD Genomics has developed a specialized platform for targeted sequencing of disease-related genes to accelerate research on disease pathogenesis, disease identification, biomarker discovery, targeted drug development, etc. CD Genomics offers predesigend NGS panels, which include a designed library of targeted sequencing, as well as a custom panel that allows customers to select genes of interest to design their own sequencing panels.
  6. In 1991, Lynne Burek published a brief commentary in the 75th anniversary issue of the American Journal of Epidemiology entitled, “The Interaction of Basic Science and Population-Based Research: Autoimmune Thyroiditis as a Case History” (1). He traced the pathways that led us from fundamental investigations in the laboratory to population studies designed to determine the factors that predict the risk of autoimmune thyroid disease before the onset of diagnostic clinical signs. In the present article, He will especially comment on the changes in the field that mark the transition into the 21st century, which reflect a combination of broadly based systematic research. The autoimmune diseases, which collectively affect more than 20 million Americans, are clinically diverse but share a fundamental etiology: a self-reactive adaptive immune response. By definition, these diseases are distinguished by the presence of B cells and T cells that recognize antigens present in the body of the host, in the form of self-reactive antibodies or T cells. In recent years, a related group of diseases has been described as sharing many of the same inflammatory mediators but lacking self-reactive lymphocytes, which are often to referred as “auto-inflammatory responses,” and these disorders usually have a clear genetic component and evidence of activation of innate immune system. According to epidemiologic studies, the incidence rates of autoimmune disorders is increasing in industrialized countries, which probably reflects some environmental changes. In addition, greater attention has been directed to these diseases because of improved diagnostic procedures and therapeutic interventions. However, for any of them, there is essentially no definitive cure. A common feature of most autoimmune diseases, is that they develop gradually, so serious tissue damage might occur before the clinical diagnosis diseases. This observation strengthens the efforts to diagnose autoimmune diseases earlier in their courses before irreversible damage occurs. These studies are interdisciplinary in nature and require the combined efforts of immunologists, epidemiologists, environmental scientists, geneticists, and clinicians. In the past decades, such collaborative teams have conducted many researches on autoimmune diseases. The primary early risk factors for induction of an autoimmune response have been identified in the genes of the major histocompatibility complex (MHC) (2). Heightened susceptibility depends on potent activation of self-antigen–specific T lymphocytes by antigen-presenting cells bearing the same MHC. In sub-sequent studies of thyroiditis in humans, an autoimmune response to particular epitopes of the thyroglobulin molecule predicted progression of disease. Other genes, inside and outside of the MHC, modify the initial autoimmune response. These immune-regulatory genes are often expressed through particular cytokines and other inflammatory media- tors and enhance or limit the disease of genetically susceptible animals selected on the basis of their MHC haplotype (3). Beyond these genetic risk factors, many internal variables can shift autoimmune responses to clinical disease that are less likely to occur. These variables include such factors as gender, age, pregnancy, and even neurologic and emotional signals. Combined with genetic factors, characteristic autoimmune antibodies are the best predictors of impending autoimmune diseases. On the basis of the earlier decades of fundamental research, the practical application of this knowledge in human susceptibility predictors is described. Because of the high genetic susceptibility of thyroiditis in their family members, children with high genetic predisposition to thyroiditis were studied, and the onset of autoantibody formation and occurrence of clinical signs in normal children were tracked. Through years of follow-up research, children with a high risk of autoimmune thyroiditis can be identified. For example, among the 19 siblings who share the MHC haplotypes with a brother or sister who has been clinically diagnosed with autoimmune thyroiditis, 17 (89%) have thyroid antibodies, and 6 of these 17 (35%) showed biochemical or physical evidence of thyroid dysfunction during the first decade of observation. Since the beginning of this study, researchers have revisited these children in disease- susceptible families on several occasions and have proposed a gradual “natural history” of autoimmune thyroiditis. The step 1 in the "natural history" begins with a combination of genetic traits, and then the step 2 is environmental exposure, such as excessive dietary iodine (5). Step 3 is marked by the production of characteristic autoantibodies to specific determinants of thyroglobulin, as well as the production of antibodies against additional thyroid-specific antigens, such as thyroid peroxidase. In step 4, subclinical thyroiditis is evidenced by a decrease in thyroxine levels. Then in step 5, thyroid-stimulating hormone is compensatoryly increased, and thyroxine is rised to normal level. Finally, step 6 is characterized by overt hypothyroidism in which the thyroxine level cannot rise, the level of thyroid-stimulating hormone is increased, and there is pathologic and clinical evidence of thyroid goiter or an atrophic thyroid gland. Because this series of steps can take many months or years, there is an opportunity to identify individuals at highest risk of developing autoimmune disorders by using genetic and functional markers and to intervene with preventive measures. The Autoimmune disease model Childhood Asthma Asthma is a chronic airway inflammatory disease. Due to the persistence of this chronic inflammatory reaction, the airway is highly reactive, and the symptoms recur when exposed to the cause. The study of the pathogenesis of asthma has evolved from the theory of sputum to the theory of chronic inflammation of the airways, and has now developed into a parallel theory of smooth muscle dysfunction and airway inflammation. Clinical treatment can also be done by repeated treatment, with emphasis on anti-inflammatory and relief of smooth muscle spasm. In the 1950s, non-selective adrenaline was used as an antispasmodic agent to treat asthma. In 1956, a selective strong short-acting β2 agonist (Short Acting Beta 2 Agonist, SABA) was introduced. In 1971, a β2 agonist (Long Acting Beta2 Agonist, LABA) came out. Oral glucocorticoids were used in the 1960s to antagonize airway inflammation, which is effective but has many side effects. In 1972, beclomethasone dipropionate (BDP) was successfully developed. In the 1980s, budesonide (BUD) and fluticasone propionate (FP) were developed. By analogy, these inhaled corticosteroids have a stronger anti-inflammatory effect on the airway, and their side effects are significantly reduced. When children are stimulated by allergens, cold air or other incentives, they often first manifest as symptoms of upper respiratory tract allergy, such as itchy eyes, itchy nose, sneezing, etc. Because infants and young children are difficult to express itching, their symptoms often only express as blinking, blowing nose, etc, and further manifest as itching, dry cough and expectoration. These symptoms usually last for hours or days before the onset of asthma. Sudden onset of wheezing is a major feature of childhood asthma. The wheezing symptoms of asthma in children vary greatly depending on the severity of asthma. Children may have high-pitched wheezing that can be heard without a stethoscope or at a distance. Due to frequent breathing or difficulty breathing, asthma symptoms in infants and young children can be expressed as mouth breathing and nose flapping, and many children may be accompanied by a cough. Under normal circumstances, dry cough will appear at the beginning of the disease. When the seizure subsides, a white mucus-like phlegm will be coughed out. In severe cases, the symptoms of asthma can be expressed as irritability, purpura, pale, and cold sweat. Physical examination revealed an increase in heart rate and wheezing in both lungs. Symptoms of heart failure may be further aggravated with jugular vein engorgement, edema, middle lung, small blisters, and enlarged liver. Signs of emphysema can be seen in children with chronic asthma, such as barrel chest and chest percussion. In the remission period, children with asthma may have no symptoms or signs, have no effect on activities, or only manifest as symptoms of allergic rhinitis and pharyngitis. A small number of children may have chest discomfort, with or without wheezing in the lungs. To be continued in Part II…
  7. To develop drugs that target specific cell surface proteins, it is helpful to understand other proteins in its vicinity. The pathology of many diseases can be understood by elucidating local biomolecular networks or microenvironments. To this end, the enzymatic proximity labeling platform is widely used to map a wider range of spatial relationships in subcellular structures. However, there has long been a search for techniques that can map the microenvironment more precisely. Geri et al describe a microenvironmental profiling platform that uses photocatalytic carbon ene generation to selectively identify protein interactions on cell membranes, a method called MicroMap (μMap). A light-triggered labeling technique that improves the spatial resolution of this type of mapping. Specifically, they relied on a photocatalyst with a very short range of energy transfer to activate a carbine-based tag that could only diffuse a small distance in water before the reaction. Using photocatalytic-antibody conjugates to spatially localize carbene generation, they demonstrated selective labeling of antibody-bound targets and their microenvironment protein neighbors. They used this technique to identify the constituent proteins of the programmed death ligand 1 (PD-L1) microenvironment in living lymphocytes and selectively label them in immune synaptic junctions. Therefore, it its a valuable system in cancer immunotherapy. About author Creative Biostructure, founded in 2005, is specialized in providing cost-effective contract services to both academia and biotech/pharmaceutical industries in the field of structural biology and membrane protein technologies. The company has developed all-in-one, gene-to-structure pipelines for the structure determination of macromolecules. With a team of experienced professionals, Creative Biostructure is able to solve the structure of many challenging proteins including GPCRs, ion channels, transporters, enzymes and viral targets. The company also provides a comprehensive list of products and other related services to facilitate research in structural biology. Creative Biostructure has also built up a unique and comprehensive Membrane Protein Screening Platform. Aiming at elucidating the fundamentals of membrane protein systems, the company provides gene-to-structure services on the purification, crystallization, structure determination and analysis of various membrane proteins.
  8. Abstract: Since SARS-CoV-2 is similar to SARS-CoV, the research of 2003 that ACE2 is an essential receptor for SARS-CoV infection can be further explored for unveiling the secret of SARS-CoV-2. An ongoing outbreak of a novel coronavirus (SARS-CoV-2) has raised global concerns. It is identified as the cause of pneumonia with unknown etiology. Since the early outbreak in Wuhan, China, it has subsequently spread to all provinces of China and many other countries. In fact, coronavirus is a relatively common human virus, which causes 10% of the common colds. However, some coronaviruses are more harmful, such as SARS-CoV and MERS- CoV and the novel coronavirus, named SARS-CoV-2. How does SARS-CoV-2 infect patients? Spike protein (including S1 and S2 subunits) is the most important pathogenic protein of coronavirus, which helps the virus to bind to the transmembrane receptor protein on the human cell membrane, thereby helping itself to enter the cell. The latest research shows that the Spike proteins of SARS-CoV-2 and SARS-CoV are more conserved, and in vitro experiments have proved that as long as the cell expresses ACE2, SARS-CoV-2 can infect cells; on the contrary, if there is no ACE2 on the cell protein, it will not be infected. Therefore, it is believed that SARS-CoV-2 is mediated into the interior of cells through the binding of Spike proteins to ACE2 proteins, which may become a breakthrough in the study of SARS-CoV-2. What is ACE2 protein? The ACE2 gene is located on the X chromosome, which encodes a type I transmembrane glycoprotein with a single extracellular catalytic domain. ACE2 has a well-known homologous gene, ACE, which is also an angiotensin-converting enzyme. ACE and ACE2 both have two domains: the amino-terminal catalytic domain and the carboxy-terminal domain). Despite similarities, ACE2 and ACE function differently. ACE's role is to convert angiotensin I (AngI) to active angiotensin II (AngII), thereby increasing hypertension. The role of ACE2 is to convert AngII to heptapeptide angiotensin 1-7 (Ang1-7), and then antagonize the blood pressure-increasing effect of AngII, which has a negative regulatory effect on the RAS system. Therefore, ACE2 functions completely differently from ACE and the two work together to balance blood pressure. Lessons from SARS Due to the function of ACE2, previous basic clinical studies have linked it with hypertension and cardiovascular disease, but in 2003, after ACE2 was identified as an essential receptor for SARS coronavirus infection, its research in this area has been carried out. And because the pathogenic mechanism of SARS-CoV-2 is highly similar to SARS of 2003, the current research of SARS is extremely informative. In 2003, researchers identified ACE2 as a functional SARS-CoV receptor by co-immunoprecipitation technology. Subsequently, ACE2 was identified as an essential receptor for SARS infection in vivo in the ACE2-knockout mouse model. However, previous studies have found that ACE2-knockout mice with lung injury have a more severe acute injury and higher mortality than the wild-type mice, suggesting that ACE2 deficiency may worsen the symptoms of acute lung injury. Therefore, ACE2-mediated degradation of AngII is important for lung protection against the pathogenesis of pneumonia causing by SARS-CoV infection. To unveil the secret of SARS-CoV-2, more research is needed, and at the same time, scientists worldwide are dedicated to finding methods of more accurate diagnosis and more efficient treatment.
  9. Despite the widespread use of radiological techniques in diagnosis and treatment, there is still no material that can protect people from radiation. Recently, researchers at the Nanoparticle Research Center at the Korea Institute of Basic Science, in collaboration with colleagues at Seoul National University, the College of Dentistry, and the Institute of Dentistry, reported an efficient and safe nanocrystal that is effective against dangerous dose radiation. By growing manganese oxide (Mn3O4) nanocrystals on cerium oxide (CeO2) nanocrystals, the group improved the catalytic activity of CeO2/Mn3O4 nanocrystals, thus avoiding the side effects of lethal radiation. HYEON Taeghwan, director of the IBS Nanoparticle Research Center (Seoul National University), said: "Reactive oxygen species (ROS) are found in many major diseases, including sepsis, cancer, cardiovascular disease and Parkinson's disease. When our body is exposed to high levels of radiation, large amounts of ROS are generated within milliseconds due to the breakdown of water molecules. These ROS severely destroy cells and eventually lead to their death." The research team used CeO2 and Mn3O4 nanoparticles for their excellent ROS scavenging ability. The challenge is how to use these antioxidant nanomaterials in a safe and economical way: although effective, CeO2 and Mn3O4 nanoparticles can only act to remove ROS at high doses, which is not only difficult to apply but also very wasteful. In recent studies, researchers have borrowed from methods commonly employed in the field of catalysis: stacking nanoparticles with different lattice parameters results in surface strain and increases oxygen vacancies on the surface of nanocrystals. "The synergistic effect of the strains produced on Mn3O4 and the increase in oxygen vacancies on the CeO2 surface improve the surface-binding affinity of ROS, thereby enhancing the catalytic activity of nanocrystals," said Han Shangen, lead author of this study. "Strain engineering of nanocrystals, which are mainly studied in the catalyst field, has now been extended to the medical field to protect cells from ROS-related diseases," said CHO Min Gee, co-first author of the study. The team examined the safety and efficacy of this novel antioxidant nanocrystal. Molecular dynamics were analyzed using an acute radiation model of human intestinal organoids. "Genes expressed by organics pretreated with CeO2/Mn3O4 nanocrystals were associated with the proliferation and maintenance of intestinal stem cells compared with the group without pretreatment, while fewer genes were associated with cell death," explained Sang-woo Lee. In a mouse study, with only a very small dose (1/360 of the amifostine injection dose), CeO2/Mn3O4 nanocrystals significantly increased the survival rate of animals to 67% and reduced oxidative stress to internal organs, circulatory system and bone marrow cells without obvious signs of toxicity. "To ensure the safe and widespread use of radioprotectants in clinical practice, it is critical to maintain high catalytic efficacy at low doses." PARK Kyungpyo, a professor in the Department of Dentistry at Seoul University, said: "This CeO2/Mn3O4 nanocrystal demonstrates its strong antioxidant effect and effectively protects our entire body even in small doses." About the Author Collected by Matexcel. At Matexcel, many surface modification techniques have been developed so that our expertise in surface chemistry made post-synthesis functionalization possible, conveniently incorporating polymers, proteins, DNA, and antibodies to synthetic nanoparticles and other nanostructured surfaces.
  10. Carbomer is a homopolymer of acrylic acid, which is cross-linked or bonded to any of several polyol allyl ethers. The chemical formula of Carbomer is C3H4O2, and the compound is usually a white powder. And it can be dissolved in water, ethanol and glycerin. Carbomer's molecules contain 56% to 58% carboxyl groups, which are weakly acidic, so its aqueous solution should be used after neutralization with alkali to reduce its irritation to the skin and mucous membranes. When carbomer is dispersed in water, due to the repulsion between the negative charges generated by the ionization of the carboxyl group, the curled polymer stretches out and expands in volume. The 1% carbomer aqueous dispersion can be neutralized with an alkaline substance to form a gel. The concentration of the commonly used carbomer aqueous dispersion is 0.1% to 3.0%. Carbomer is well known for its use in the cosmetics industry and personal care industry, and it is often used as a thickener and emulsion stabilizer, mainly to help control the viscosity and flow of cosmetics. It helps to disperse and suspend insoluble solids in the liquid and prevents the oil and liquid parts of the solution from separating. Carbomer has the ability to absorb and retain moisture, and when swelled in water it can swell to 1000 times its original volume. Carbomer series products (Carbomer 934, Carbomer 940, Carbomer 941, Carbomer 980) are all similar in chemical properties, but their molecular weight and viscosity are different from each other. The codes of the Carbomer series products (ie 910, 934, 940, 941 and 934P) indicate the molecular weight and specific components of the polymer. Powder carbomer is commonly used in skin care products and cosmetics, while liquid carbomer is mainly used in cleaning products. At present, powder carbomer is generally added to disinfection and sterilization products on the market. In the past few years, Carbomer's global market has developed rapidly, with an average growth rate of 11.98% from 2013 to 2017. In 2018, the global carbomer market was valued at US$722.9 million and is expected to reach US$17.951 billion by 2028, with a compound annual growth rate of 9.3%. Carbomer's series products include Carbomer 940, Carbomer 980, Carbomer 934, etc. In 2018, Carbomer 940's market share is about 37%. Carbomer is widely used in the pharmaceutical, personal care and cosmetic industries. Carbomer is most used in the personal care and cosmetics industries, with a proportion of about 54%. Carbomer is commonly used as a thickener, dispersant, suspending agent and emulsifier in cosmetics and personal care products. By adding carbomer to shampoo, conditioner, cream and lotion, these makeup and cleansing products will become smoother. It can also be used in styling gel, sunscreens, eye creams, and scrubs. Clinical studies have shown that carbomer polymers are less likely to cause skin irritation and sensitization at concentrations as high as 100%. Furthermore, carbomer polymers show low phototoxicity and photocontact sensitization potential.
  11. Updates: BMS recently published the result of the critical phase III True North study (NCT02435992) that assessed Zeposia (ozanimod) as an induction and maintenance therapy for adult patients with moderate to severe ulcerative colitis (UC). It is worth mentioning that Zeposia is the first in history an oral sphingosine-1-phosphate (S1P) receptor modulator to show clinical benefits. Facts Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) manifesting bloody stools, severe diarrhea, and frequent abdominal pain, usually over time rather than suddenly, which is characterized by abnormal immune response, long duration, long-term inflammation and ulcer in the colonic mucosa. To the therapies currently available, many patients do not respond adequately or at all, seriously influencing their physical function, social and emotional health and work ability. It is estimated that 12.6 million people worldwide are suffering from IBD. Pathopoiesis Mechanism 1. Sulfide in Diet The toxic effect of sulfide on colon cells may be a major cause. The proportion of protein in diet increases as the adjustment of people's dietary habits, resulting in the sharply climbing intake of sulfur-containing amino acids (including methionine, cysteine, cystine and taurine). Through the degradation and fermentation of such amino acids by intestinal bacteria, a variety of sulfur-containing compounds are produced. The accumulation of hydrogen sulfide in the intestine may have a certain direct toxic effect on colon cells, and may also indirectly change the protein function and antigenicity. Research shows that the intake of meat (rich in protein), especially red meat and processed meat, increases the risk of UC recurrence. In addition, due to the non organic sulfate (including sulfur dioxide, hydrogen sulfide, sulfite) is widely used as preservative in the storage and storage of food and beverage, such as hamburger, concentrated beverage, sausage, beer and red wine, etc. Therefore, these foods and drinks also increase the risk of UC. 2. Dietary Fat Excessive intake of fat or unsaturated fatty acid will damage the colonic mucosa, result in colitis, and may also affect the absorption and secretion of cholesterol. The hypercoagulable state formed by hypercholesterolemia can cause vasospasm, increase the tension of blood vessels, and affect the blood supply of mucosa, which therefore may cause colon mucosa damage. Excessive intake of monounsaturated fatty acids and polyunsaturated fatty acids may increase the incidence of UC. 3. Carbohydrate High sugar intake may be related to UC. According to an epidemiological survey, people who often eat foods with high sugar content, such as cola drinks and chocolate have a positive correlation with UC, compared with those who jointly eat vegetables and fruits. The pathogenesis of UC caused by high sugar diet is not clear so far. Diagnosis Conventional approaches of UC diagnosis like clinical evaluation (symptoms), radiology and endoscopy, in conjunction with histological examinations and imaging techniques are costly and time-consuming. Non-invasive diagnostic tests on serological biomarkers (p-ANCA, ASCA, CBir1, anti-I2, etc.) and stool markers (infectious pathogens like calprotectin and lactoferrin) in easily obtained biological samples with IVD immunoassays are receiving popularity recent years, which have been well developed into various platforms, including ELISA, LFIA, CLIA, IHC, etc. In March 2020, Zeposia was approved by the U.S. FDA for the treatment of adult multiple sclerosis (clinically isolated syndrome, recurrent remission disease and active secondary progressive disease), which in May got approved by the European Commission to treat adult patients with relapsing remitting multiple sclerosis (RRMS) with active disease manifesting clinical or imaging characteristics. UC is an unpredictable and potentially debilitating disease. The results of the True North study are very encouraging for patients with moderate to severe UC due to the consistent efficacy at key clinical and endoscopic endpoints, suggesting that Zeposia may address the need for new oral therapies.
  12. The Parallel Artificial Membrane Permeation Assay (PAMPA) is a non-cell based assay designed to predict passive, trans- cellular permeability of drugs in early drug discovery. In this assay, we will discuss the major concerns related to PAMPA. PAMPA analysis measures the permeability of artificial membranes that provides an in vitro model of passive diffusion. Passive diffusion is an important factor that determines transport through the gastrointestinal tract, penetration of the blood-brain barrier, and transport across cell membranes. Permeability may also be affected by several other mechanisms, including paracellular transport and active uptake or efflux not evaluated in PAMPA. Therefore, PAMPA can provide a simplified permeability method by measuring a single mechanism which avoids the complexity of active transport/outflow and enables compounds to be ordered by a single permeability. Generally, PAMPA is used as the main permeability barrier, in which a simple measurement of passive diffusion is required. However, separation using PAMPA may misunderstand the true understanding of permeability in vivo. Cell-based analysis (e.g. Caco-2) evaluates permeability through passive diffusion across cells and active and paracellular transport. Therefore, Caco-2 permeability screen can provide more detailed mechanical information. What is the relationship between Caco-2 and PAMPA? PAMPA measures permeability only by passive diffusion, while the Caco-2 permeability assay also evaluates active uptake/efflux and paracellular transport. Therefore, if the compound only passes through the membrane by passive diffusion, a good correlation is observed between the Caco-2 permeability measurement and PAMPA. If the compound is an active substrate, PAMPA will overestimate the permeability, if the compound undergoes active uptake or paracellular absorption, PAMPA will underestimate the permeability. The relationship between Caco-2 permeability and PAMPA permeability can be used to diagnose the penetration mechanism. The penetration of these compounds is dominated by passive diffusion, unrelated compounds are divided into two subsets. A subset has a higher PAMPA permeability than the cell monolayer permeability and is composed of compounds affected by secretion mechanisms: efflux of alkali or reduced passive diffusion under Caco-2 when operating under a pH gradient. The cell monolayer permeability of the other subset is higher than that of PAMPA, and consists of compounds with an absorption mechanism: when running under a pH gradient, the absorption of acid under the Caco-2 is increased by the paracellular uptake, active transport or passive diffusion. In view of the characteristics of these two methods, these studies show how to synergistically apply PAMPA and Caco-2 to the rapid and effective study of the penetration mechanism in drug discovery. In the early discovery process, PAMPA can be used to quickly screen all compounds at low and neutral pH to evaluate passive diffusion permeability to indicate the potential of gastrointestinal tract and cells to measure penetration. In the middle of the discovery process, selected compounds can also be analyzed by Caco-2, which goes to the outside of the basal. This result, combined with PAMPA data, shows sensitivity to other penetration mechanisms (secretion and absorption). During the mid- to late-stage discovery, selected candidates can be examined in detail through multiple targeted Caco-2 experiments and transporter inhibitors to fully characterize the penetration mechanism. All compounds can be quickly screened using PAMPA at low and neutral pH to assess passive diffusion permeability to indicate the potential of the gastrointestinal tract and cells to measure penetration.
  13. Oncolytic virus (OV) is a kind of natural or genetically modified virus that can specifically infect and kill tumor cells without causing too many harmful effects on normal cells. Initially, the world authoritative medical journal TheLancet reported that influenza viruses will cause tumors in patients to regress, resulting in the oncolytic virus, and then researchers around the world have carried out a series of studies on this, and now there are more than 160 different oncolytic viruses preclinical research and clinical trials are underway. However, due to the strong immunogenicity of oncolytic viruses, when injected into the body intravenously, it will trigger the body to produce different degrees of immune responses, which will quickly clear the virus by the body. In addition, the tumor targeting of oncolytic viruses is limited, resulting in their inability to specifically reach the tumor site through the blood circulation, which seriously affects the tumor suppressive effect of oncolytic viruses, and produces different degrees of adverse reactions. In order to solve the above drawbacks, researchers construct different types of vectors to load oncolytic viruses to block their immunogenicity, extend their blood circulation time, and further combine oncolytic viruses with chemotherapy, radiotherapy, immunotherapy, photodynamic therapy, photothermal therapy and other combination of treatment means to improve its tumor treatment effect. Construction of oncolytic virus vectors based on biological materials Biomaterials can be used to load oncolytic viruses to achieve the purpose of blocking viral immunogenicity and achieving targeted delivery of tumors. The biomaterials currently used for oncolytic virus loading mainly include liposomes, cells or extracellular vesicles. Liposome expressing oncolytic virus Cationic liposomes constructed with (2,3-dioleoyl-propyl)-trimethylamine (2,3-dioleoy-loxy-propy)-trimethylammonium (DOTAP) encapsulate oncolytic adenovirus, which can block the surface of adenovirus, reduces its immunogenicity, and allows the oncolytic adenovirus to enter the Coxsackie virus-adenovirus receptor (CAR) low-expressing tumor cells to replicate through endocytosis. However, after entering the body, cationic liposomes will adsorb some negatively charged serum proteins, causing the liposome nanoparticles to agglomerate, which seriously affects their access to the tumor site through the enhanced permeability and retention effect (EPR effect). Anionic liposomes are endogenous components of eukaryotic cell membranes. Compared with cationic liposomes, they have the advantages of low toxicity and low immunogenicity. They have been widely used in recent years. At the same time, there are studies that claim that anionic liposomes can undergo a phase change under the action of calcium ions, which is conducive to the liposomes encapsulating oncolytic viruses through electrostatic adsorption. PEG (polyethylene glycol) anionic liposome based on matrix metalloproteinase and substrate peptide/cholesterol, successfully encapsulated oncolytic adenovirus, its research team confirmed the high gene expression efficiency of the material in vitro, while the safety of the material was confirmed by C57BL/6N mice. Cell or extracellular vesicles expressing oncolytic virus Commonly used cell carriers such as stem cells, lymphocytes, and tumor-related cells have good tumor chemotaxis. Coupling the oncolytic virus on the surface of the cell or loading it into the cell can not only effectively block the immunogenicity of the virus, but also improve its targeted enrichment effect on tumors. Studies showed that stem cells have a tendency to affect the tumor microenvironment and have a low immunogenicity. On this basis, JOSIAH and others used adipose-derived stem cell (ADSC) from healthy mice for the first time to load myxoma oncolytic virus, then it was injected into tumor-bearing mice to achieve the targeted delivery of the virus to glioma. In addition, some researchers used mesenchymal stem cell (MSC) expressing Newcastle discase virus (NDV). The results found that in vitro MSC can not only improve the targeting of NDV to glioma cells, but also the secretion of TNF-related apoptosis-inducing ligand (TRAIL), which significantly improve the oncolytic effect of the virus on glioma stem cells. In addition, there are studies used immature dendritic cells (iDC) and lymphokine-activated killer cells (LAK) to coordinately transport reovirus, which killed ovarian cancer cells in vitro by resisting neutralizing antibodies in patients' ascites. LANKOV et al. reported for the first time that using tumor-associated macrophages as a carrier of oncolytic measles virus to delivery mice ovarian cancer, this strategy allows the virus to evade the neutralization of antibodies and complement, and then the virus can be transferred to tumor cells through in situ cell fusion. Extracellular vesicles are a subcellular structure with membrane components secreted by almost all cells, including exosomes, microvesicles, and membrane particles, which also play an important role in drug delivery. LV et al. designed an engineered cell membrane nanovesicle containing targeting ligands for delivery of oncolytic adenoviruses (OA@BCMNs). This system showed strong resistance in a variety of tumor-bearing mouse models. The tumor effect can significantly prolong the survival time of mice without major adverse reactions. Tumor extracellular vesicles with a similar membrane structure to tumor cells can also be used as an ideal carrier for oncolytic viruses. Due to their homologous targeting, this system can also achieve tumor-targeted delivery of oncolytic viruses. A study used tumor cell-derived microparticles (T-MP) to deliver oncolytic adenovirus, and the constructed nanoparticles (oncolytic adenovirus-microparticle (OA-MP) can not only make the virus escape the body's resistance viral effect, and can make the oncolytic virus enter into the nucleus of tumor cells or tumor stem cells to self-replicate without relying on the receptor-mediated infection. Therefore, this system is also more effective for tumor cells with low CAR receptor expression, such as human chronic myeloid leukemia cells (K562 cells). Construction of oncolytic virus vectors based on non-biological materials The non-biological carrier material mainly encapsulates the virus through two reaction modes: covalent action and non-covalent action. Covalent modification is to use amino acid residues on the envelope or capsid protein of the virus surface to couple with other molecules through covalent action, and non-covalent modification is to use electrostatic adsorption, hydrogen bonding, van der Waals force, or antigen-antibody action. The modification is coupled to the virus. Oncolytic viruses with high molecular polymers Due to the ease of preparation and good biocompatibility of high molecular polymers, they have the advantages of being metabolizable and degradable in the body, which has attracted extensive attention in the medical field, such as drug loading, delivery and release. Since most viral proteins are negatively charged under physiological conditions, many cationic polymer complexes can be adsorbed on the virus surface by electrostatic action. TESFAY et al. encapsulated FSL-PEG2000 on the surface of vesicular stomatitis virus (VSV) through electrostatic adsorption; therefore, the virus surface protein was effectively blocked, thereby effectively reducing the antibody neutralization effect in mouse serum and the effect of mice liver and spleen on virus storage. However, because virus infection depends on the specific recognition of its surface proteins and host cell surface receptors, and the coating of FSL-PEG2000 affects the recognition and infection of viruses and tumor cells, the follow-up research aims to find some controllable polymer, which allows the oncolytic virus to be released in a targeted manner when it reaches the host cell without affecting its ability to infect. Environmental stimuli-responsive polymer can respond to small changes in the outside world, so this feature can be used to achieve on-site release of oncolytic viruses. CHOI et al. used physical adsorption method to wrap the pH-sensitive polymer (mPEG-b-pHis) on the surface of adenovirus to prepare a stable oncolytic adenovirus complex, which not only reduces the immune response of adenovirus, but also release the oncolytic virus under the slight acid environment of the tumor, and then restore the virus to the tumor cells. Based on the same principle as above, LEE et al. utilized biodegradable macromolecular polymer cholic acid coupled polyvinylamide [bileacid-conjugated Poly(ethylencimine), DA3] encapsulates adenovirus, and the constructed viral nanocomposite particles (Ad/DA3) can also effectively increase the effect of virus in vitro to a variety of tumor cells. To be continued in Part Two…
  14. 1.3. Blood system diseases HSC was first used for blood diseases, and it is the most mature. Both autogenous HSC and foreign HSC are used. And they are mainly used for some hematological malignancies, such as acute myeloid leukemia, acute lymphocytic leukemia, Hodgkin lymphoma, non-Hodgkin lymphoma, aplastic anemia, etc. All have achieved good results and improved the 10-year survival rate of patients, but it is ineffective for some patients, such as low diploid leukemia. Hematopoietic stem cell transplantation is generally used after chemotherapy. It can differentiate into myeloid progenitor cells, lymphoid progenitor cells, etc. in the human body, and then produce blood cells of various lineages. The treatment of blood system diseases is mainly through cell replacement. Eventually The effect is to rebuild the functional hematopoietic system and immune system. It is now found that multiple myeloma and sickle cell disease can also benefit from HSCs transplantation. For patients with poor conventional treatment or relapse, stem cell transplantation is still effective and can improve the cure rate. However, before transplantation, the patient's physical tolerance, blood system status and human leukocyte antigen typing must be fully considered to avoid the occurrence of GVHD. 1.4. Bone and joint system diseases The human osteoblasts have the ability to proliferate and differentiate. When the damage is not serious, the bone itself can undergo a certain degree of self-repair. For more severe bone and cartilage injuries, especially when there are a large number of bone defects, local blood supply, and oral and maxillofacial fractures that do not heal, stem cell transplantation still plays a very important role. From the source of bone and joint development, mesenchymal stem cells derived from mesoderm are the most widely used in bone and joint diseases. Mesenchymal stem cells can migrate to the site of injury and differentiate into osteoblasts and chondrocytes to repair bone damage. In osteoarthritis and sports injuries, stem cell therapy has been found to reduce pain, repair cartilage degradation, and promote motor function recovery. The mechanism of stem cell treatment of bone and joint diseases is multi-faceted, including paracrine function, improving microenvironment, promoting angiogenesis, replacement repair, etc. It is currently believed that the main role is to improve the local microenvironment of bone injury. 1.5. Eye diseases The application of stem cell transplantation in ophthalmology is mainly to promote the repair of cornea and retina. There are a certain number of stem cells inside the eye tissue, mainly limbal stem cells (LSC), which is also a class of stem cells that are widely used in ophthalmology. It has a certain therapeutic effect on corneal injury and limbal stem cell deficiency, but it faces a limited source and immune rejection during allogeneic transplantation, which limits a large range of clinical applications. Fat or bone marrow-derived MSCs are another ideal cell type, and have certain therapeutic effects on glaucoma, retinal pigment degeneration, and macular atrophic damage combined with retinal yellow spots (Stargardt disease). Animal studies have found that MSCs can differentiate into photoreceptors and retinal pigment epithelial cells, secrete neurotrophic factors, and inhibit the apoptosis of optic nerve cells, and transplantation under the retina is more effective than intravitreal. Clinical studies have found that MSCs can migrate into the macular area of the retina and improve the patient's vision, but the effect almost disappears after 1 year. Considering that the cell type is not suitable for growth in the eye, it is only a short-term effect that occurs through the secretion of trophic factors. In addition: ESCs or i PSC-derived retinal pigment epithelial cells and oral mucosal epithelial cells can also be selected, and it has a therapeutic effect on patients with age-related macular degeneration and retinitis pigmentosa. Because MSCs and HSCs have a wide range of sources, the preparation difficulty is relatively low, the safety is good, the paracrine and immunomodulatory effects are strong, so they are currently widely used. In addition to the diseases mentioned above, there are many diseases that may benefit from stem cell transplantation. Type 2 diabetes is essentially an autoimmune disease mediated by T cells. Therefore, the use of MSCs or HSCs can regulate immune function, inhibit T cell activation and inflammatory factor production, so as to relieve the symptoms of diabetes and reduce the amount of insulin. In addition, other diseases such as hepatitis, cirrhosis, burns, skin damage, systemic lupus erythematosus, rheumatoid arthritis, intestinal Crohn's disease, acute respiratory distress syndrome and other diseases have also been studied using mesenchymal stem cell therapy. To ensure the success of stem cell therapy, we must first solve the problem of stem cell survival and migration after transplantation. Many studies have found that the stem cells transplanted into the body have a short survival time and cannot differentiate into target cells and function. Therefore, ensuring the homing, survival, differentiation and normal migration of transplanted stem cells is the key to effective treatment. There have been attempts to combine drugs (sodium ferulate, lithium valproate, erythropoietin), or related physical therapy (shock wave), or pre-treatment of stem cells (endothelial nitric oxide synthase) during the culture stage Enhancer, and embedding stem cells into biological materials (such as hydrogels, fabricated scaffolds) to increase the success rate of stem cell transplantation. For the problem of low cell differentiation efficiency in vivo, direct transplantation of totipotent stem cells should be avoided as far as possible, and high-purity tissue-specific precursor cells can be differentiated in vitro for transplantation, which also reduces the risk of tumorigenesis. Secondly, stem cells exist in many tissues and organs of the human body. Extracting and applying these stem cells is a good choice, but the problem is to obtain sufficient and effective stem cells. During the in vitro expansion process, the characteristics of stem cells may change to some extent, making them no longer suitable for repairing damaged tissues. Moreover, after the occurrence of the disease, the microenvironment of the lesion has undergone tremendous changes, which will also adversely affect the survival and migration of stem cells after transplantation. Finally, the standardization of stem cell preparation and transplantation, including the number and purity of stem cells, cell viability, route of administration, frequency, transplantation site, and the optimal time for treatment, all require careful evaluation and selection. It is important to establish a set of stem cell preparation and expansion standardized procedures for augmentation, storage and transplantation to achieve a stable treatment effect. References [1] Ferraro F,Celso CL,Scadden D. Adult stem cels and their niches[J].Adv Exp Med Biol,2010,695:155-168. [2] Ito Y,Nakamura S,Sugimoto N,et al. Turbulence activates platelet biogenesis to enable clinical scale ex vivo production[J]. Cell,2018,174(3):636-648. [3] Regueiro A,Cuadrado-Godia E,Bueno-Beti C,et al. Mobilization of endothelial progenitor cells in acute cardiovascular events in the PROCELL study:time-course after acute myocardial infarction and stroke[J]. J Mol Cell Cardiol,2015,80:146-155. [4] Bochon B,Kozubska M,Suryga?a G,et al. Mesenchymal stem cells-potential applications in kidney diseases[J]. Int J Mol Sci,2019,20(10):2462. [5] Ming GL,Song H. Adult neurogenesis in the mammalian brain:significant answers and significant questions[J]. Neuron,2011,70(4):687-702.
  15. The principle of SNP genotyping technology is PCR amplification of genomic fragments containing SNP. The main features are high accuracy, strong flexibility and high throughput. The main method is the TaqMan probe method. Technical principles SNP genotyping First, the SNP-containing genomic fragments are amplified by PCR, and then single-base extension is achieved by sequence-specific primers. Then, the sample analyte and the chip matrix are co-crystallized and then excited by an intense nanosecond (10-9s) intense laser in a vacuum tube. Nucleic acid molecules are desorbed into single-charged ions. Because the flight time of ions in the electric field is inversely proportional to the ion mass, the precise molecular weight of the sample analyte is obtained by detecting the flight time of the nucleic acid molecules in the vacuum tube, thereby detecting SNP site information. Main features The accuracy of SNP detection achieved by time-of-flight mass spectrometry (MALDI-TOF) can reach 99.9%. In addition to the advantages of high accuracy, flexibility, high throughput, and short detection cycle, the most attractive should be its cost performance. The time-of-flight mass spectrometry platform (MALDI-TOF) is an internationally-used research platform for genetic single nucleotide polymorphism (SNP). This method has become a new standard in this field with its scientificity and accuracy. Main methods TaqMan probe method Design PCR primers and TaqMan probes for different SNP sites on chromosomes respectively, and perform real-time fluorescent PCR amplification. The 5'-end and 3'-end of the probe are labeled with a reporter fluorescent group and a quenching fluorescent group, respectively. When the PCR product is present in the solution, the probe is annealed to the template, which produces a substrate suitable for exonuclease activity, thereby cleaving the fluorescent molecule attached to the 5'-end of the probe from the probe, destroying the two PRET between fluorescent molecules emits fluorescence. Usually used for small SNP loci analysis. SNaPshot method   This technology was developed by American Applied Biology Company (ABI), and it is a typing technology based on the principle of single base extension of fluorescent labeling, also known as small sequencing, which is mainly aimed at medium-throughput SNP typing projects. In a reaction system containing sequencing enzymes, four fluorescently labeled ddNTPs, different length extension primers and PCR product templates immediately adjacent to the 5'-end of the polymorphic site, the primer extension is terminated by one base, and after detection by the ABI sequencer, The SNP site corresponding to the extension product is determined according to the shifting position of the peak, and the type of the incorporated base can be known according to the color of the peak, thereby determining the genotype of the sample. The PCR product template can be obtained by multiple PCR reaction system. Usually used for 10-30 SNP loci analysis. The HRM method high-resolution melting curve analysis (HRM) is a SNP research tool that has emerged in recent years. It detects the presence of SNPs by monitoring the combination of double-stranded DNA fluorescent dyes and PCR amplification products during real-time heating. Moreover, different SNP sites and whether they are heterozygotes will affect the peak shape of the melting curve, so HRM analysis can effectively distinguish between different SNP sites and different genotypes. This detection method is not limited by the location and type of the mutated base. No sequence-specific probes are required. After the PCR is completed, high-resolution melting is run directly to complete the analysis of the sample genotype. The method does not need to design a probe, and the operation is simple, fast, low in cost, accurate in result, and realizes the real closed tube operation. Mass Array method  MassARRAY molecular weight array technology is the world's leading gene analysis tool launched by Sequenom. It combines primer extension or cleavage reaction with sensitive and reliable MALDI-TOF-MS technology to achieve genotyping detection. The iPLEX GOLD technology based on the MassARRAY platform can design up to 40-fold PCR reaction and genotype detection, with flexible experimental design and high accuracy of typing results. According to the needs of the application, when testing hundreds to thousands of samples from dozens to hundreds of SNP sites, MassARRAY has the best cost performance, especially suitable for verifying the results of genome-wide research findings, or a limited number of the situation where the research site has been determined. Illumina BeadXpress method uses Illumina's BeadXpress system for batch SNP site detection, which can detect 1-384 SNP sites at the same time. It is often used to confirm the results of genomic chips and is suitable for high-throughput detection. The microbead chip has the characteristics of high density, high repeatability, high sensitivity, low sample load, flexible customization, etc., and extremely high integration density, thus obtaining extremely high detection screening speed, and can significantly reduce costs during high-throughput screening. About us We work hard to offer you the same dependable services to pharmaceutical and biotech companies, as well as academia and government agencies for satisfying all your sequencing or array needs. Through nearly ten year's hard working and depend on our professional work team, we are proud of satisfying the needs of our clients both at home and abroad, which across more than 50 countries and districts. We always devote ourselves to providing you with the best and professional service. Here are some: pacific biosciences, Total RNA Sequencing, human genome, gbs sequencing, etc.